热压时间对Laves相Cr_2Nb合金组织与性能的影响  

Effect of hot pressing time on microstructure and properties of laves phase Cr_2Nb alloy

作　　者：肖璇[1] 鲁世强[2] 胡平[2] 黄铭刚[2] 聂小武[2] 

机构地区：[1]南京航空航天大学机电学院,江苏南京210016 [2]南昌航空工业学院材料学院,江西南昌330063

出　　处：《材料热处理学报》2007年第6期59-62,共4页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(50474009);航空科学基金(05G56003);江西省自然科学基金(0350045)

摘　　要：采用机械合金化+热压工艺路线制备化学配比成分的单相Laves相Cr2Nb合金。研究了Cr、Nb元素粉经20h球磨后在1300℃不同时间热压所获得的Laves相Cr2Nb合金的组织性能。结果表明,采用机械合金化+热压工艺可以制备出高致密度的组织细小均匀的Laves相Cr2Nb合金,随着热压时间的延长,合金的致密度、晶粒尺寸和维氏硬度逐渐增大而断裂韧度逐渐减小。1300℃×30min的热压试样的平均晶粒尺寸达到亚微米级,致密度达到98.7%,断裂韧度达到5.07MPa.m1/2,与熔铸法制备的Laves相Cr2Nb相比,室温断裂韧性提高,实现了细晶组织对Laves相Cr2Nb合金的增韧效果。Laves phase Cr2 Nb alloy was prepared by mechanical alloying with stoichiometfic niobium and chromium powders and subsequent hot pressing at 1300℃ for different time. The microstructure and mechanical properties of the alloy were investigated by optical microscope,SEM and mechanical property test. The results indicate that Laves phase Cr2 Nb alloy with homogeneous microstructure and fine grains and high relative density is obtained by mechanical alloying and hot pressing. With the increase of hot pressing time, the relative density, grain size and Vickers hardness increase but the fracture toughness decreases gradually. The alloy hot pressed at 1300℃ for 30 minutes has a relative density of 98.7% and a room temperature fracture toughness of 5.07MPa·m^1/2. Compared with Laves phase Cr2Nb alloy with a fracture toughness of 1.2MPa·m^1/2 prepared by are-melting, the fracture toughness of Laves phase Cr2Nb alloy prepared here increases greatly, the effect of fine grain toughening has been fully realized.

关 键 词：机械合金化 热压 Laves相Cr2Nb 增韧 组织与性能 

分 类 号：TG132.3[一般工业技术—材料科学与工程]